HSVTac: A High-Speed Vision-Based Tactile Sensor for Exploring Fingertip Tactile Sensitivity

The sensitivity of human tactile perception is essential in sensing texture surfaces via the fingertip. However, direct investigation of the underlying physiological principles is challenging due to their complexity, while bionic vision-based tactile sensing is a promising solution. This article proposed a novel high-speed vision-based tactile sensor, denoted as HSVTac, which emulated the functional characteristics of the human fingertip. A high-speed camera with 2200 frames/s covered the frequency response range of four mechanoreceptor types, which mediated the coding of tactile stimuli. The sinusoidal vibration stimulation was applied to verify that the frequency range reached 0-600 Hz. Then, a sliding contact paradigm was designed, and two experiments were conducted with 54 types of gratings texture surfaces. Variations in gratings' width and sliding direction characterized spatial acuity, and variations in gratings' period and sliding velocity characterized temporal sensitivity. The spatial acuity and temporal sensitivity recognition rates reached 91.20% and 92.59%, respectively. The results demonstrated that the high-frequency information promoted tactile sensitivity and enhanced discrimination of texture surfaces. The proposed device represented a novel approach to investigating human tactile perception and provided the necessary equipment foundation for assessing tactile sensitivity.